This project investigates the syndrome of multiple personality disorder (MPD). The investigation continues to focus on three major areas. The first is the physiologic and neurophysiologic differences reported to exist among the alternate personality states. The existence of certain types of differences has been documented and further research is underway to elucidate the mechanisms of these state-related changes. The second is on the symptoms, presentation, and phenomenology of the clonical syndrome. An extensive case finding study is underway, sampling cases in treatment in the United States abroad. The third focus is on a prospective study of cases currently in treatment to clarify the long-term outcome of this unusual disorder.